Iris image data processing for use with iris recognition system

ABSTRACT

The present invention relates to an iris recognition method which is one of biometric technologies. According to a non-contact-type human iris recognition method by correction of a rotated iris image of the present invention, the iris image is acquired by image acquisition equipment using an infrared illuminator. Inner and outer boundaries of the iris are detected by analyzing differences in pixels of a Canny edge detector and the image for the inputted iris image, so as to allow the boundaries of the iris to be more accurately detected from the eye image of a user. Thus, the iris image with a variety of deformation can be processed into a correct iris image, so that there is an advantage in that a false acceptance rate and a false rejection rate can be markedly reduce.

RELATED APPLICATIONS

[0001] This application is a continuing application under 35 U.S.C. §365 (c) claiming the benefit of the filing date of PCT Application No.PCT/KR01/01302 designating the United States, filed Jul. 31, 2001. ThePCT Application was published in English as WO 02/071316 A1 on Sep. 12,2002, and claims the benefit of the earlier filing date of Korean PatentApplication No. 2001/11441, filed Mar. 6, 2001. The contents of theKorean Patent Application No. 2001/11441 and the internationalapplication No. PCT/KR01/01302 including the publication WO 02/071316 A1are incorporated herein by reference in their entirety.

FIELD OF INVENTION

[0002] The present invention relates to a non-contact-type human irisrecognition method by correction of a rotated iris image. Moreparticularly, the present invention relates to a non-contact-type humaniris recognition method by correction of a rotated iris image, whereinthe iris image is acquired by image acquisition equipment using aninfrared illuminator, wherein inner and outer boundaries of the iris aredetected by analyzing differences in pixels of a Canny edge detector andthe image for the inputted iris image, so as to allow the boundaries ofthe iris to be more accurately detected from the eye image of a user,wherein if the iris in the eye image acquired by the image acquisitionequipment has been rotated at an arbitrary angle with respect to acenterline of the iris, the rotated iris image is then corrected into anormal iris image, and wherein if a lower portion of a converted irisimage in polar coordinates is curved with an irregular shape due to theacquisition of the slanted iris image, the iris image is normalized inpredetermined dimensions, so that the iris image with a variety ofdeformation can be processed into a correct iris image.

BACKGROUND OF INVENTION

[0003] An iris recognition system is an apparatus for identifyingpersonal identity by distinguishing one's own peculiar iris pattern. Theiris recognition system is superior in its accuracy in terms of thepersonal identification in comparison to the other biometric methodssuch as voice or fingerprint, and it has a high degree of security. Theiris is a region existing between the pupil and the white sclera of aneye. The iris recognition method is a technique for identifying personalidentities based on information obtained by analyzing respective one'sown iris patterns different from each other.

[0004] Generally, the kernel technique of the iris recognition system isto acquire a more accurate eye image by using image acquisitionequipment and to efficiently acquire unique characteristic informationon the iris from the inputted eye image.

[0005] However, in a non-contact type human iris recognition systemwhich acquires an iris image to be taken at a certain distancetherefrom, the iris image with a variety of deformation may be acquiredin practical. That is, it is unlikely that a complete eye image can beacquired since the eye is not necessarily directed toward a front faceof a camera but positioned at a slight angle with respect to the camera.Thus, there may be a case where the information on an eye image rotatedat an arbitrary angle with respect to a centerline of the iris isacquired.

[0006] Therefore, in order to solve the above problem produced in theprocess of image acquisition, it is necessary to accurately detectinner/outer boundaries of the iris from the eye image of a user and tonormalize the iris image extracted from the eye image. However,conventional iris recognition methods have a problem in that they cannotaccurately detect the inner/outer boundaries of the iris since upondetection of the boundaries, critical values are manually assigned torespective images after defining an arbitrary center of the pupil, or amean value of the entire image is used as the critical value.

[0007] Furthermore, according to the conventional iris recognitionsystem, since the normalization process of the iris image is not made orthe correction to the rotated image is not considered, an incomplete eyeimage can be acquired if the eye is not directed toward the front faceof the camera but positioned at a slight angle with respect to thecamera, or a rotated iris image can be acquired due to movement of theuser such as tilting of his/her head. Consequently, there were manycases where in spite of an iris image of the same user, the iris imagemay be falsely recognized as that of another user.

SUMMARY OF THE INVENTION

[0008] One aspect of the present invention is to provides a method ofdetecting an outer boundary of an iris from an image of an eye. Themethod comprises: providing data representing an image of an eyecomprising an image of the iris of the eye, the iris image beingsubstantially annular and defined between inner and outer boundaries,the eye image comprising a plurality of pixels, the eye image datacomprising location information and image information for each pixel ofthe eye image; providing location information of the inner boundary ofthe iris image; comparing the image information of a pixel on the innerboundary with the image information of pixels of the eye image; anddetermining a pixel is on the outer boundary of the iris image when adifference between the image information of that pixel and the imageinformation of the pixel on the inner boundary becomes a maximum amongdifferences of the image information. In the above-described method, thelocation information of the inner boundary is obtained with use of aCanny edge detection method.

[0009] Another aspect of the present invention provides a method ofobtaining an iris pattern. The method comprises: providing an image ofan iris of an eye, the iris image being substantially annular anddefined between inner and outer boundaries; obtaining data of asubstantial portion, but not all, of the iris image; and processing thedata of the substantial portion to obtain an iris pattern. In theabove-described method, the data comprises positional information andimage information of a point within the portion. The substantial portionof the iris image is from about 25% to about 95% of an area of the irisimage. The substantial portion of the iris image is from about 40% toabout 85% of an area of the iris image. The substantial portion of theiris image is from about 50% to about 75% of an area of the iris image.The substantial portion of the iris image is from about 55% to about 65%of an area of the iris image. The substantial portion of the iris imageis substantially annular. The substantial portion is annular and definedfrom the inner boundary to an imaginary closed line between the innerand outer boundaries. The imaginary closed line is substantiallyparallel to the inner boundary.

[0010] Still in the above-described method, a tangent at a point on theinner boundary is substantially parallel to a tangent at a point on theimaginary line that is on a line perpendicular to the tangent at thepoint on the inner boundary. The substantial portion is annular anddefined from an imaginary closed line between the inner and outerboundaries to the outer boundary. The imaginary closed line issubstantially parallel to the outer boundary. The substantial portion isannular and defined between a first imaginary closed line and a secondimaginary closed line, wherein the first imaginary line is drawn betweenthe inner and outer boundaries, and wherein the second imaginary line isdrawn between the first imaginary line and the outer boundary. The firstand second lines are substantially parallel to each other. Thesubstantial portion of the iris image is not annular. The data of thesubstantial portion is transformed into a polar coordinate form.

[0011] A further aspect of the present invention provides a device foruse with a iris pattern recognition system. The method comprises: meansfor providing an image of an iris of an eye, the iris image beingsubstantially annular and defined between inner and outer boundaries;means for obtaining data of a substantial portion, but not all, of theiris image; and means for processing the data of the substantial portionto obtain an iris pattern. In the above-described device, an iris imageprocessing device comprises: an input device configured to receive animage of an eye comprising an image of an iris of an eye, the iris imagebeing substantially annular and defined between inner and outerboundaries; a first circuit configured to identify data of the irisimage from the image of the eye; and a second circuit configured toprocess the iris image data so as to obtain data of a substantialportion, but not all, of the iris image for further processing. Thefirst and second circuits are integrated in a circuit board or a chip.

[0012] The other aspect of the present invention is a security systemusing iris pattern recognition. The system comprises: an input deviceconfigured to receive an image of an eye comprising an image of an irisof an eye, the iris image being substantially annular and definedbetween inner and outer boundaries; a first circuit configured toidentify data of the iris image from the image of the eye; a secondcircuit configured to process the iris image data so as to obtain dataof a substantial portion, but not all, of the iris image for furtherprocessing; and a third circuit configured to process the data of thesubstantial portion of the iris image so as to determine whether thedata of the iris image matches a pre-registered data.

[0013] A further aspect of the present invention is a method ofprocessing a iris image. The method comprises: providing data of anoriginal image of an iris; and producing at least one modified irisimage data with use of the data of the original iris image, the modifiediris image data representing an iris image that is rotated by an angleabout a point on the original image. In the above-described method thepoint of rotation is located at a substantially central position of theoriginal image of the iris. The original iris image data to determinewhether the original iris image data matches a pre-registered iris imagedata. The modified iris image data to determine whether the modifiediris image data matches a pre-registered iris image data. The modifiediris image data represents an iris image that is rotated in a clockwisedirection. The modified iris image data represents an iris image that isrotated in a counter-clockwise direction. A plurality of modified irisimage data are produced. The modified iris image data is processed inaccordance with a wavelet transform method. The original iris image datais processed in accordance with a wavelet transform method.

[0014] Still another aspect of the present invention provides an irisimage processing device, which comprises: means for providing data of anoriginal image of an iris; and means for producing at least one modifiediris image data based on the data of the original iris image, themodified iris image data representing an iris image that is rotated byan angle about a point on the original image. The above-described devicefurther comprises: means for determining whether the modified iris imagedata matches a pre-registered data.

[0015] Still another aspect of the present invention provides an irisimage processing device, which comprises: an input device configured toreceive an image of an eye comprising an image of an iris of an eye; afirst circuit configured to identify data of the iris image from theimage of the eye; and a second circuit configured to process the irisimage data so as to produce at least one modified iris image data basedon the data of the original iris image, the modified iris image datarepresenting an iris image that is rotated by an angle about a point onthe original image.

[0016] Still further aspect of the present invention provides a securitysystem using iris pattern recognition, which comprises: theabove-desciribed iris image processing device; and a third circuitconfigured to process the modified iris image data to determine whetherthe modified iris image data matches a pre-registered data.

[0017] The present invention is conceived to solve the above problems.An object of the present invention is to provide a non-contact typehuman iris recognition method for performing a pre-processing bydetecting an iris image from an eye image of a user acquired by imageacquisition equipment and converting the iris image into an iris imagein polar coordinates, wherein inner and outer boundaries of an iris ofthe user are detected by analyzing differences in pixels of a Canny edgedetector and the image.

[0018] Another object of the present invention is to provide a humaniris recognition method, wherein if an iris in an acquired eye image hasbeen rotated at an arbitrary angle with respect to a centerline of theiris, i.e. in case of a rotated iris image, the rotated iris image iscorrected into a normal iris image, and wherein if a lower portion of aconverted iris image in the polar coordinates is curved with anirregular shape, i.e. in case of a slanted iris image, the iris image isnormalized in predetermined dimensions, so that the iris image with avariety of deformation is processed into data on a correct iris image soas to markedly reduce a false acceptance rate and a false rejectionrate.

[0019] In order to achieve the objects of the present invention, thepresent invention provides a non-contact type human iris recognitionmethod by correction of a rotated iris image for performing apre-processing by acquiring an eye image of a user by means of imageacquisition equipment using an infrared illuminator, by extracting aniris image from the acquired user's eye image, and by converting theextracted iris image into an iris image in polar coordinates. Thepre-processing comprises the steps of detecting an inner boundary of aniris from the acquired user's eye image by means of a Canny edgedetector; comparing a pixel value of image information at a beginningcoordinates (x, y) of the detected inner boundary of the iris with theother pixel values of image information while proceeding upward anddownward and leftward and rightward from the inner boundary, finding outthe maximum value among values of difference in the compared pixels, anddetecting an outer boundary of the iris; and extracting an iris regionexisting between the inner and outer boundaries, and converting theextracted iris region into the iris image in the polar coordinates.

[0020] If the iris in the acquired eye image has been slanted, themethod may further comprise a step of normalizing the converted irisimage in the polar coordinates so as to have predetermined dimensions.

[0021] If the iris in the acquired eye image has been rotated at anarbitrary angle with respect to a centerline of the iris, the method mayfurther comprise the steps of temporarily generating a plurality ofarrays of the iris image by means of shifts by an arbitrary angle withrespect to an array of the converted iris image in the polarcoordinates; performing wavelet transform in order to generatecharacteristic vectors of the iris corresponding to the plurality ofarrays of the iris image that have been temporarily generated; comparingthe respective characteristic vectors generated by the wavelet transformwith previously registered characteristic vectors to obtainsimilarities; and accepting a characteristic vector corresponding to themaximum similarity among the obtained similarities as the characteristicvector of the user.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]FIG. 1 is a flowchart explaining the procedures of a normalizationprocess of an iris image according to the present invention.

[0023]FIG. 2a is a view showing a result of detection of a pupillaryboundary using a Canny edge detector.

[0024]FIG. 2b is a view showing center coordinates and diameter of apupil.

[0025]FIG. 2c shows an iris image upon obtainment of a radius and centerof an outer boundary of an iris according to the present invention.

[0026] FIGS. 3 (a) to (d) show the procedures of the normalizationprocess of a slanted iris image.

[0027] FIGS. 4 (a) and (b) show a rotated iris image resulting from thetilting of the user's head.

[0028] FIGS. 5 (a) and (b) show procedures of a correction process ofthe rotated iris image shown in FIGS. 4 (a) and (b).

DETAILED DESCRIPTION FOR PREFERRED EMBODIMENT

[0029] Hereinafter, a non-contact type human iris recognition method bycorrection of a rotated iris image according to the present inventionwill be described in detail with reference to the accompanying drawingsand, in particular, to FIG. 1.

[0030]FIG. 1 is a flowchart explaining procedures of a normalizationprocess of an iris image according to the present invention. Referringto FIG. 1, at step 110, an eye image is acquired by image acquisitionequipment using an infrared illuminator and a visible light rejectionfilter. At this time, a reflective light is caused to be gathered in thepupil of an eye so that information on the iris image is not lost. Atstep 120, inner and outer boundaries of the iris are detected in orderto extract only an iris region from the acquired eye image, and thecenter of the detected inner and outer boundaries is set. Step 120 isperformed by a method for detecting the inner and outer boundaries ofthe iris using differences in pixels of a Canny edge detector and theimage according to the present invention, which will be specificallyexplained below.

[0031]FIG. 2a is a view showing a result of detection of a pupillaryboundary, i.e. the inner boundary of the iris, using the Canny edgedetector. Referring to FIG. 2a, it is noted that only the pupillaryboundary is detected by employing the Canny edge detector. That is, asshown in FIG. 2a, the inner boundary of the iris is detected by usingthe Canny edge detector that is a kind of boundary detecting filter. TheCanny edge detector smoothes an acquired image by using Gaussianfiltering and then detects a boundary by using a Sobel operator. TheGaussian filtering process can be expressed as the following Equation 1,and the used Sobel operator can be expressed as the following Equation2.

[0032] [Equation 1]

I _(G)(x, y)=G(x, y)×I(x, y)  [Equation 1]

[0033] $\begin{matrix}{{S_{x} = {{{I\left\lbrack {i - 1} \right\rbrack}\left\lbrack {j + 1} \right\rbrack} + {2{{I\lbrack i\rbrack}\left\lbrack {j + 1} \right\rbrack}} + {{I\left\lbrack {i + 1} \right\rbrack}\left\lbrack {j + 1} \right\rbrack} - {{I\left\lbrack {i - 1} \right\rbrack}\left\lbrack {j - 1} \right\rbrack} - {2{{I\lbrack i\rbrack}\left\lbrack {j - 1} \right\rbrack}} - {{I\left\lbrack {i + 1} \right\rbrack}\left\lbrack {j - 1} \right\rbrack}}}{S_{y} = {{{I\left\lbrack {i + 1} \right\rbrack}\left\lbrack {j + 1} \right\rbrack} + {2{{I\left\lbrack {i + 1} \right\rbrack}\lbrack j\rbrack}} + {{I\left\lbrack {i + 1} \right\rbrack}\left\lbrack {j - 1} \right\rbrack} - {{I\left\lbrack {i - 1} \right\rbrack}\left\lbrack {j + 1} \right\rbrack} - {2{{I\left\lbrack {i - 1} \right\rbrack}\lbrack j\rbrack}} - {{I\left\lbrack {i - 1} \right\rbrack}\left\lbrack {j - 1} \right\rbrack}}}} & \left\lbrack {{Equation}\quad 2} \right\rbrack\end{matrix}$

[0034] In a case where the boundary detecting method employing the Cannyedge detector is used, even though a normal eye image is not acquiredsince the eye of a user is not directed toward a front face of a camerabut positioned at a slight angle with respect to the camera, the innerboundary of the iris, i.e. papillary boundary, can be correctly detectedand center coordinates and radius of the pupil can also be easilyobtained. FIG. 2b shows the center coordinates and diameter of thepupil. Referring to FIG. 2b, the pupil's radius is d/2, and the pupil'scenter coordinates are (x+d/2, y+d/2).

[0035] On the other hand, the outer boundary of the iris in the imagecan be detected by comparing pixel values while proceeding upward anddownward and leftward and rightward from the pupillary boundary, i.e.the inner boundary of the iris, and by finding out maximum values ofdifferences in the pixel values. The detected maximum values areMax{I(x, y)−I(x−1, y)}, Max{I(x, y)−I(x+1, y)}, Max{I(x, y)−I(x, y−1)},and Max{I(x, y)−I(x, y+1)}, where I(x, y) is a pixel value of the imageat a point of (x, y). The reason why the differences in the pixel valuesare obtained while proceeding upward and downward and leftward andrightward from the inner boundary of the iris upon detection of theouter boundary of the iris in the image is to make the inner and outercenters different from each other. That is, in a case where a slantediris image is acquired, since the pupil is located a little upward,downward, leftward or rightward of the image, the inner and outercenters should be set differently from each other.

[0036]FIG. 2c shows an iris image upon obtainment of the radius andcenter of the outer boundary of the iris according to the presentinvention. In a case where an incomplete eye image is acquired since theeye is not directed toward the front face of the camera but positionedat a slight angle with respect to the camera, a process of setting thecenters of the inner/outer boundaries of the iris is required. First,values of distances R_(L), R_(R), R_(U) and R_(D) from the innerboundary to the left, right, upper and lower portions of the outerboundary, respectively, and a value of the radius RI of the innerboundary, i.e. pupillary boundary, are calculated. Then, the center ofthe outer boundary is obtained by finding out bisection points upwardand downward and leftward and rightward of the image using the abovecalculated values.

[0037] At step 130, iris patterns are detected only at predeterminedportions of the distances from the inner boundary to the outer boundary.At step 140, the detected iris pattern is converted into an iris imagein the polar coordinates. At step 150, the converted iris image in thepolar coordinates is normalized to obtain an image having predetermineddimensions in its width and height.

[0038] The conversion of the extracted iris patterns into the iris imagein the polar coordinates can be expressed as the following Equation 3.

I(x(r, θ), y(r, θ))

I(r, θ)  [Equation 3]

[0039] where θ is increased by 0.8 degrees, and r is calculated by usingthe second Cosine Rule from a distance between the outer center C_(O)and the inner center C_(I) of the iris, the radius R_(O) of the outerboundary, and the value of θ. The iris patterns between the inner andouter boundaries of the iris are extracted using the r and θ. In orderto avoid changes in features of the iris according to variations in thesize of the pupil, when the iris image between the inner and outerboundaries of the iris is divided into 60 segments and the θ is variedby 0.8 degrees to represent 450 data, the iris image is finallynormalized into a 27000 segmented iris image (θ×r=450×60).

[0040]FIG. 3 (a) shows the slanted iris image, and FIG. 3 (b) is theiris image in polar coordinates converted from the slanted iris image.It can be seen from FIG. 3 (b) that a lower portion of the convertediris image in the polar coordinates is curved with an irregular shape.In addition, FIG. 3 (c) shows an iris image having the dimensions of Mpixels in width and N pixels in height, which is normalized from theirregular image of the iris patterns. Hereinafter, the normalizationprocess of the slanted iris image will be described with reference toFIGS. 3 (a) to (c). In the portion corresponding to the distance betweenthe inner and outer boundaries of the iris in FIG. 3 (a), the irispatterns existing at only a portion corresponding to X % of the distancebetween the inner and outer boundaries of the iris are taken in order toeliminate interference from the illuminator and acquire a large amountof iris patterns. That is, when the inner and outer boundaries of theiris are detected, the iris patterns are taken and then converted intothose in the polar coordinates. However, in a case where reflectivelight from the illuminator is gathered on the iris, iris patternsexisting at only a portion corresponding to 60% of the distance from theinner boundary among the region from the inner boundary (pupillaryboundary) of the iris to the outer boundary can be picked up andconverted into those in the polar coordinates. The value of 60% selectedin this embodiment of the present invention was experimentallydetermined as a range in which a greatest deal of iris patterns can bepicked up while excluding the reflective light gathered on the iris.

[0041] In FIG. 3 (b), the slanted iris image is converted into the irisimage in the polar coordinates. As shown in FIG. 3 (b), when the irispatterns are converted into those in the polar coordinates, the lowerportion of the converted iris pattern image in the polar coordinates iscurved with an irregular shape. Thus, it is necessary to normalize theirregular iris pattern image. In FIG. 3 (c), the irregular image of theiris patterns is normalized to obtain the iris image with the dimensionsof M pixels in width and N pixels in height.

[0042] For reference, the performance of the iris recognition system isevaluated by two factors: a false acceptance rate (FAR) and a falserejection rate (FRR). The FAR means the probability that the irisrecognition system incorrectly identifies an impostor as an enrollee andthus allows entrance of the impostor, and the FRR means the probabilitythat the iris recognition system incorrectly identifies the enrollee asan impostor and thus rejects entrance to the enrollee. According to thepresent invention, when a pre-processing is made by employing the methodfor detecting the boundaries of the iris and the normalization of theslanted iris image, the FAR was reduced from 5.5% to 2.83% and the FRRis reduced from 5.0% to 2.0% as compared with the iris recognitionsystem employing a conventional method for detecting the boundaries ofthe iris.

What is claimed is:
 1. A method of detecting an outer boundary of aniris from an image of an eye, the method comprising: providing datarepresenting an image of an eye comprising an image of the iris of theeye, the iris image being substantially annular and defined betweeninner and outer boundaries, the eye image comprising a plurality ofpixels, the eye image data comprising location information and imageinformation for each pixel of the eye image; providing locationinformation of the inner boundary of the iris image; comparing the imageinformation of a pixel on the inner boundary with the image informationof pixels of the eye image; and determining a pixel is on the outerboundary of the iris image when a difference between the imageinformation of that pixel and the image information of the pixel on theinner boundary becomes a maximum among differences of the imageinformation.
 2. The method of claim 1, wherein the location informationof the inner boundary is obtained with use of a Canny edge detectionmethod.
 3. A method of obtaining an iris pattern, comprising: providingan image of an iris of an eye, the iris image being substantiallyannular and defined between inner and outer boundaries; obtaining dataof a substantial portion, but not all, of the iris image; and processingthe data of the substantial portion to obtain an iris pattern.
 4. Themethod of claim 3, wherein the data comprises positional information andimage information of a point within the portion.
 5. The method of claim3, wherein the substantial portion of the iris image is from about 25%to about 95% of an area of the iris image.
 6. The method of claim 3,wherein the substantial portion of the iris image is from about 40% toabout 85% of an area of the iris image.
 7. The method of claim 3,wherein the substantial portion of the iris image is from about 50% toabout 75% of an area of the iris image.
 8. The method of claim 3,wherein the substantial portion of the iris image is from about 55% toabout 65% of an area of the iris image.
 9. The method of claim 3,wherein the substantial portion of the iris image is substantiallyannular.
 10. The method of claim 3, wherein the substantial portion isannular and defined from the inner boundary to an imaginary closed linebetween the inner and outer boundaries.
 11. The method of claim 10,wherein the imaginary closed line is substantially parallel to the innerboundary.
 12. The method of claim 11, wherein a tangent at a point onthe inner boundary is substantially parallel to a tangent at a point onthe imaginary line that is on a line perpendicular to the tangent at thepoint on the inner boundary.
 13. The method of claim 3, wherein thesubstantial portion is annular and defined from an imaginary closed linebetween the inner and outer boundaries to the outer boundary.
 14. Themethod of claim 13, wherein the imaginary closed line is substantiallyparallel to the outer boundary.
 15. The method of claim 3, wherein thesubstantial portion is annular and defined between a first imaginaryclosed line and a second imaginary closed line, wherein the firstimaginary line is drawn between the inner and outer boundaries, andwherein the second imaginary line is drawn between the first imaginaryline and the outer boundary.
 16. The method of claim 15, wherein thefirst and second lines are substantially parallel to each other.
 17. Themethod of claim 3, wherein the substantial portion of the iris image isnot annular.
 18. The method of claim 3, wherein the data of thesubstantial portion is transformed into a polar coordinate form.
 19. Adevice for use with a iris pattern recognition system, comprising: meansfor providing an image of an iris of an eye, the iris image beingsubstantially annular and defined between inner and outer boundaries;means for obtaining data of a substantial portion, but not all, of theiris image; and means for processing the data of the substantial portionto obtain an iris pattern.
 20. An iris image processing device,comprising: an input device configured to receive an image of an eyecomprising an image of an iris of an eye, the iris image beingsubstantially annular and defined between inner and outer boundaries; afirst circuit configured to identify data of the iris image from theimage of the eye; and a second circuit configured to process the irisimage data so as to obtain data of a substantial portion, but not all,of the iris image for further processing.
 21. The device of claim 20,wherein the first and second circuits are integrated in a circuit boardor a chip.
 22. A security system using iris pattern recognition,comprising: an input device configured to receive an image of an eyecomprising an image of an iris of an eye, the iris image beingsubstantially annular and defined between inner and outer boundaries; afirst circuit configured to identify data of the iris image from theimage of the eye; a second circuit configured to process the iris imagedata so as to obtain data of a substantial portion, but not all, of theiris image for further processing; and a third circuit configured toprocess the data of the substantial portion of the iris image so as todetermine whether the data of the iris image matches a pre-registereddata.
 23. A method of processing a iris image, comprising: providingdata of an original image of an iris; and producing at least onemodified iris image data with use of the data of the original irisimage, the modified iris image data representing an iris image that isrotated by an angle about a point on the original image.
 24. The methodof claim 23, wherein the point of rotation is located at a substantiallycentral position of the original image of the iris.
 25. The method ofclaim 23, further comprising processing the original iris image data todetermine whether the original iris image data matches a pre-registerediris image data.
 26. The method of claim 23, further comprisingprocessing the modified iris image data to determine whether themodified iris image data matches a pre-registered iris image data. 27.The method of claim 23, wherein the modified iris image data representsan iris image that is rotated in a clockwise direction.
 28. The methodof claim 23, wherein the modified iris image data represents an irisimage that is rotated in a counter-clockwise direction.
 29. The methodof claim 23, wherein a plurality of modified iris image data areproduced.
 30. The method of claim 23, wherein the modified iris imagedata is processed in accordance with a wavelet transform method.
 31. Themethod of claim 23, wherein the original iris image data is processed inaccordance with a wavelet transform method.
 32. An iris image processingdevice, comprising: means for providing data of an original image of aniris; and means for producing at least one modified iris image databased on the data of the original iris image, the modified iris imagedata representing an iris image that is rotated by an angle about apoint on the original image.
 33. The device of claim 32, furthercomprising: means for determining whether the modified iris image datamatches a pre-registered data.
 34. An iris image processing device,comprising: an input device configured to receive an image of an eyecomprising an image of an iris of an eye; a first circuit configured toidentify data of the iris image from the image of the eye; and a secondcircuit configured to process the iris image data so as to produce atleast one modified iris image data based on the data of the originaliris image, the modified iris image data representing an iris image thatis rotated by an angle about a point on the original image.
 35. Asecurity system using iris pattern recognition, comprising: the irisimage processing device of claim 34; and a third circuit configured toprocess the modified iris image data to determine whether the modifiediris image data matches a pre-registered data.